Telephone call processing and switching systems are, at the time of the present patent application, relatively sophisticated, computerized systems, and development and introduction of new systems continues. Much information on the nature of such hardware and software is available in a number of publications accessible to the present inventors and to those with skill in the art in general. For this reason, much minute detail of known systems is not reproduced here. One document which provides considerable information on intelligent networks is “ITU-T Recommendation Q.1219, Intelligent Network User's Guide for Capability Set 1” dated April, 1994. This document is incorporated herein by reference.
Telephony applications have enabled communications centers to service clients in ways that are relatively efficient and that provide considerable sharing of information between call points and end users. Today, telephony applications are intelligent systems capable of being installed and used within the local network as well as within the larger Internet or other suitable networks.
A large technical support operation serves as a good example in this specification of the kind of application of telephony equipment and functions to which the present invention pertains and applies, and a technical support organization will be used from time to time in the current specification for exemplary purposes. Such a technical support system, as well as other such systems, typically has a countrywide or even worldwide matrix of call centers for serving customer's needs. Such call center operations are more and more a common practice to provide redundancy and decentralization.
In a conventional call center, a relatively large number of agents handle telephone communication with callers. Each agent is typically assigned to a telephone connected to a central switch, which is in turn connected to a public-switched telephone network (PSTN), well known in the art. The central switch may be one of several types, such as a Private Branch Exchange (PBX) for example. An automated call distributor (ACD) is another common type of call switch. Often a service control point (SCP) switch, which may be a PBX, is typically available within a network segment for accepting first-party calls local to the switch and routing those calls to other destination points, such as regional call centers.
Intelligent call routing and processing may be on several levels. Pre-routing may be done at SCPs and further routing may be, and almost always is, accomplished from individual call centers. As described above a call center typically involves a central switch, which may be, for example, an Automatic Call Distributor (ACD), or a Private Branch Exchange (PBX). The central switch is connected to the PSTN, as is well known in the art. Agents, trained to handle customer service, man telephones connected to the central switch. The local equipment is often referred to in the art as Customer Premises Equipment (CPE).
If the call center consists of just a central switch and connected telephone stations, the routing that can be done is very limited. Switches, such as ACD and PBX and the like, although increasingly computerized, are limited in the range of computer processes that may be performed. For this reason additional computer capability in the art has been added for such central switches by connecting computer servers adapted to run control routines and to access databases. The processes of incorporating computer enhancement to telephone switches is known in the art as Computer Telephony Integration (CTI), and the hardware and software used is referred to as CTI equipment.
In a CTI-enhanced system telephone stations connected to the central switch may be equipped also with computer terminals, so agents manning such stations may have access to stored data as well as being linked to incoming callers by a telephone connection. Such stations may be interconnected in a network by any one of several known network protocols, with one or more servers also connected to the network one or more of which may also be connected to a processor providing CTI enhancement, also connected to the central switch of the call center. It is this processor that provides the CTI enhancement for the call center.
When a call arrives at a call center, whether or not the call has been pre-processed at a SCP, typically the telephone carrier (network provider) makes the telephone number of the calling line available to the receiving switch at the call center in one of several known formats.
In state-of-art systems known to the inventor, complex call routing and processing is accomplished using extra intelligence beyond that of a normal switch. CTI processors may be made available at network level and at end service points to help route calls more efficiently and to provide robust information about the call and call parties. In many cases, both in service and business communication call states change or are modified when being established in a network. For example, the number of parties to a call can change dynamically or from different points of control.
It is possible that when calls are established between different PBXs, for example, information about the call including current call-state information may be lost in the process. A typical example of a call established by more than one switch where information may not be available to all parties is exemplified by the following exemplary description:
A first caller (C1) initiates and establishes a connection through a first PBX (PBX1) to a second caller (C2) monitored by the same PBX. C2 may after being established in session with C1 decide to bring a third caller (C3) into the conversation through a second PBX (PBX2) so that all three callers may conference. However, C3 may only receive caller identification information about C2 because C2 is the sole party that initiated the addition of C3 by placing an additional call to C3 and then bridging the party connection at PBX2.
A problem with current art call handling among multiple switches is that for each state change, defined as a possible call state related to one or more actual or potential parties of a call, the latest PBX has no information that C1, for example, is already in a session with C2. Likewise, C1 will receive no information about C3 except by voice after state has changed or on word of C2. The only bi-directional identification information exchange is between C1 and C2 (root). Depending on the business scenario, C1 may not wish to conference with C3 without proper identification. Likewise, C3 may be unaware of C1 and may not wish to participate if the identity of C1 were known to C2. This example reflects a simple three-party scenario and it will be appreciated by the skilled artisan that more than three parties and more than two switches may be involved in a complex multiparty session.
Therefore, what is clearly needed is a system that enables multiple PBXs involved in servicing a multiparty communication session to share information about all call-related events that may occur in an active multiparty session including the identification information of all of the parties and potential current call or connection states of the parties involved.